Since the free volume available to the colloids decreases with increasing \(\phi _L\) , one might expect this increase in the number of isostatic particles, and hence an increase in \(L_\text{iso}^\text{ss}\)  in the filled system. Furthermore, the gel phase boundary for unfilled systems, \(\epsilon ^*_0(\phi _S)\) , is a decreasing function of \(\phi _S\) , at least at low to moderate concentrations [1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}, [10]}. This suggests the possibility of capturing the shifting gel point with granular inclusions simply in terms of the reduced free volume available to the colloids. In this picture, one would expect the filler to have more pronounced effect at lower colloid concentrations, where the curve \(\epsilon ^*_0(\phi _S)\)  is steepest. However, simulations with \(\phi _S=0.1\) 
instead show the opposite, with the inclusion of large grains giving only a modest increase in \(L_\text{iso}^\text{ss}\)  (Fig. REF D) and minor shifts in the gelation phase boundary.
<FIGURE><FIGURE>